Plaquemines Parish employees, with floodlights and Bobcats, began throwing up a chest-high makeshift levee across Lousiana 23 as the first bands of rain and wind from Hurricane Gustav began sweeping over the parish.

Officials on the scene said the work could continue for the next five hours as dump trucks haul in mud and limestone to secure sand-filled Hesco baskets. A ramp over the levee will allow vehicles coming from the south to evacuate.

"All night and this morning it looked like it was going to be no use," Parish President Billy Nungesser said of the parish's efforts to shore up shaky areas of the levees. "But now it's looking like it's worth it to go out there and make every effort to fill the gaps."

Despite signs of promise in weather forecasts, parish officials were still concerned about privately maintained levees that run along the highway and stretch west, some of which Nungesser said reach only three or four feet high in places.

Nungesser said keeping the highways dry will be critical for speeding the recovery, allowing businesses to get back on their feet quickly, should storm surge sweep the south end of the peninsula.

Nungesser left the parish emergency operations center just before 6 p.m. to make a last-ditch appeal to Belle Chasse citizens to leave the area. He estimated that several thousand remain. Of 20 residents he encountered earlier in the day on the southern tip of the parish, seven agreed to go, he said.

"Every person I can convince to leave is one less person we have to pull off a roof later," he said.

Earlier, Maj. John Marie, deputy chief of operations for the Plaquemines Parish Sheriff's Office, said officials had succeeded in getting most parish residents to flee as emergency managers braced for the possibility that storm surge could overtop levees and threaten Belle Chasse with flooding for the first time in its history.

Emergency officials said that scenario is still possible, but they were heartened by more recent weather reports showing Gustav weakening slightly and moving at a brisk pace, which could lessen the stress on flood barriers.

Marie said the parish was locked down at 6 p.m. so deputies could be pulled out of harm's way.

Emergency officials will be leaving the parish emergency operations center and setting up on the second floor of Belle Chasse High School.

As the storm approached there were few signs of lingering residents. The main highway corridor was quiet with only an occasional straggler and the flashing lights of police cars. Residential cul-de-sacs appeared abandoned, vehicles sat parked on high ground and windows were boarded.